Trailer for road vehicles



I INVENTOR. BY CECIL h/Booslv ATTORNEY.

Jan; '7, 1941. c. w. BODEN TRAILER FOR ROAD VEHICLES Flled July 8, 1938Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE TRAILER FOR ROADVEHICLES Cecil W. Boden, Oakland, Calif.

Application July 8, 1938, Serial No. 218,173

3 Claims. (Cl. 16-44) The invention concerns trailers for road vehicles,and more particularly relates to wheel devices for supporting suchtrailers from the road.

An object of the invention is to provide a generally improved trailerwheel unit of the caster type which will not weave or shimmy whiletravelling aionga road at a high speed.

Another object is to provide a wheel caster having an improved shockabsorbing means which is equally operative for all possible directionsof travel of the wheel, and operates without undue slap or reboundeffects.

A further object'is to provide a wheel caster assembly of the characterdescribed which is of minimum thickness transversely of the wheel planeand is particularly simple in structure.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth or be apparent in thefollowing description of a typical embodiment thereof, and in theaccompanying drawing, in

which Figure l is a perspective view showing a trailer provided with asupporting wheel caster embody- 2& ing the features of the presentinvention,

Figure 2 is a side elevation of the caster. Figure 3 is a perspectiveview of a unitary fork member of the caster assembly.

Figure 4 is a rear view of the caster having its wheel removed and aportion of the structure broken out and shown in section.

Figure 5 is a sectional view at 5-5 in Figure 4. As is particularlyillustrated, the features of the present invention are incorporated inthe structure of a trailer 7 which comprises a loadsupporting frame 8having its front end pivotally and supportedly secured to laterallyspaced bumper-supporting bars 9, or other members, which extendrearwardly from the body of an automobile It, or other motor drivenvehicle fortravel on the highways. The pivotal connection between thebars 9 and the frame 8 is provided by suitable hitch assemblies H whichare cooperative to provide pivotal connections between the bars and sidemembers of the frame 8, it

being understood that the arrangement maintains the longitudinalalignment of the frame with the vehicle as an extension of the vehiclebody to which-it is hinged by the assemblies H.

A load-receiving platform or bed I2 is shown as being mounted on theframe 8, and represents any suitable body for the trailer.

' As is usual with trailers which are arranged to move or swinglaterally as part. of the towing vehicle, the trailer load is preferablyarranged to be supported mainly from the roadway and upon a wheel casteri4. having its swivelling axis upright and being fixed to and beneaththe frame 8 toward its rear end and in its longitudinal center linewhereby the two vehicle connectionsand 5 the caster M cooperativelyprovide a three-point support for the trailer frame and its load. Thearrangement is preferably such that the trailer frame 8 is substantiallyparallel to the plane of the supporting roadway thereat. 1c

The presentcaster assembly i4 essentially comprises a wheel i5rotatively mounted between the legs of a fork l6 which is hinged to amember H which is in turn swiveled to a base or bracket it fixed to theframe 8. The arrangement is such 15 that the swiveling axis of themember I1 is perpendicular to the plane of the frame 8, and the axis ofrotation of the wheel i5 and the axis of hinging of the fork I6 aremutually parallel to each other and said frame plane. Also, it is to be20 noted that, as is usual with trailer casters, the wheel axis isdisposed rearwardly of the swivel axis as the caster wheel rollsforwardly along a supporting roadway; this is provided by having thecommon plane of the wheel and hinging axes 2g of the fork oblique to theroad plane, and results in the engagement of the wheel tread with theroad at a point rearwardly of the intersection of the swivel axis withthe road.

The legs 2! of the fork it are laterally spaced so apart to freelyreceive the wheel it between them, said wheel being provided with apneumatic tire 22 of suitable size. The wheel hub 23 is mounted on ashaft 24 which is engaged in and between the lower extremities of thefork legs 2!. Mutually spaced and parallel ears 25 depend from the underside of the member if for the simultaneous disposal of their mutuallyopposite faces in close proximity to the opposed inner faces of the forklegs 2| at the upper an ends thereof, and mutually aligned bores throughthe ears 25 and said upper fork ends receive a hinge pin 26 for hingingthe fork and member I! together for relative rotation about the pinaxis. Preferably, and as indicated in Figure 4, the 45 pin 26 isarranged for a tight fit in the ears 25 and may be spot-welded to theears in set position as is shown at 21; in thismanner, the fork isarranged for its pivotal movement-about the ends of the pin 25 which isflush with the outer 5 fork faces at its opposite ends whereby tominimize the necessary width of the assembly at the hinge pin. Ifdesired, the bearing bores of the fork legs may be provided with hearingbushings, as is shown. u

It will-now be noted that the under face of the member I! above the ears25 is generally parallel to the frame 8 and extends forwardly from abovethe hinge pin 26, and that the fork legs 2i are integrally joined by aU-shaped fork portion which extends forwardly of thehinge pin 26 andaround the ears 25. As shown, said legconnecting fork portion comprisesforward lateral extensions 28 of the fork legs 2| connected 10 by a flatpart which extends in general parallelism to said under face of themember I1 and in spaced relation thereto.

The member I'I provides a forwardly extending arm 3I whichlies oppositethe arm provided by the fork portions 28 and 29, and said arms areprovided with mutually aligned perforations therethrough which freelyreceive a bolt 32 which is disposed in generally perpendicular relationto the plane of the portion 29, and in the wheel plane. The upper boltend is pivoted to the extension or arm 3|; as shown, a terminal eye 33of the bolt is disposed between upstanding ears 34 of the arm 3I andreceives a pivot pin 35 which is fixed in and between said ears. At itslower end, the bolt 32 mounts a nut 36 between which and the under sideof the fork portion 29 a compression spring 31 is engaged; as shown,

a depression in the under face of the arm .29 and an upwardly flangeddisc 38' engaging the upper face of the nut 36 provide centering seatsfor the spring extremities. A bumper ring 39 of rubber or the likeencircles the bolt between the extension 3| and the fork portion 29 as aresilient means to yieldingly resist and limit the movement of the arms29- and 3I toward each other; it will be understood that the arm 29 isnormally held centered by and betwen the spring 31 and the spring ring39 for its oscillation about the hinging of the fork, the bolt 32 being40 operative under tension. a

With the descrbed spring arrangement at and in connection with the bolt32, it will be understood that when the forward-travelling wheel I5strikes a projection in the road, the fork legs are temporarily swungupwardly and rearwardly against the increasing resistance of the spring31, and that a return movement beyond the initial fork position isresisted by the bumper spring 39. The present provision of but one shockabsorbing spring 31 and but one rebound absorbing spring 39 in mutuallycoaxial alignment and in the plane of the caster wheel provides a casterassembly of minimum width and also one in which road thrusts areconfined to said plane and so cannot cause binding effects on the pin-26 or in the swivel connections.

It will now be noted that the base member I8 is generally rectangularfor its fitted engagement between parallel cross-members 40 of thetrailer frame 3, is provided with upstanding perforated ears H for usein bolting it to the members 48, and is provided with bottom sideflanges 42 for seating against the under edges of the members 48 forcarrying the weight of the trailer on the member I8. A cylindricalextension or stem 43 extends upwardly from the flat upper face of themember I1 and is journalled in a complementary upright bore providedthrough the base member I8. Preferably, and as shown, the stem-receiving7o bore of the base I8 is provided with a bearin bushing .44, and abearing ring 45 is engaged between the opposed bottom and top faces ofthe' base I8 and member II. A cap-screw 46 is axially engaged in thestem 43 to releasably fix an overlying disc 47 thereto, said discextending opposite the upper face of the base member to secure the stemin the base and complete the swiveled connection of the member I1 andI8.

Considering the described caster as a unit, it will be particularlynoted that the upright swivel axis defined at the stem 43 is somewhatahead of the horizontal hinging axis for the wheel-carrying fork of theassembly, and that this arrangement is operative to prevent a weaving orshimmying action of thewheel on the road. Also, the hinging of the forkI8 to the member I! which is swiveled to the trailer frame provides .ashock-absorbing arrangement which is equally operative for all possibledirections of the caster wheel with respect to the trailer, since itturns with the wheel and is constantly operative in the wheel plane.When the trailer is loaded, the weight of the load on the caster willnormally compress the spring 31 somewhat whereby the load will beresiliently supported in part on the spring 31, it being noted that theeffective lever arm of the fork about the hinge pin 21 constantlyexceeds the effective lever arm for the resistance offered by the spring31, for the permitted range nection with the accompanying drawing, theadvantages of the caster of my invention will be readily understood bythose skilled in the art to which the invention appertains. While I havedescribed the principle of operation, together with an arrangement whichI now consider to be a preferred embodiment thereof, I desire to have itunderstood that the embodiment shown is primarily illustrative, and thatsuch changes may be made, when desired, as fall within the scope of thefollowing claims.

1. In a wheel caster, a base, a trailing fork and wheel assembly, anintermediate member hinged to the fork and swiveled to the base at axeswhich are respectively parallel to the wheel axis and upright, mutuallyspaced arms extending forwardly from the member and fork respec-' tivelyin a common upright plane including the swivel axis, a bolt pivoted to asaid arm and extending freely through the other arm in the plane of thearms, a compression spring means operative at the bolt and between thefree bolt end and the second arm, and a compression spring meansoperative at the bolt and between said arms.

'2. A structure in accordance with claim 1 wherein the arms and bolt arecoplanar with the wheel, and the bolt is pivoted to the arm of theintermediate member.

3. A structure in accordance with claim 1 wherein the bolt is coplanarwith the wheel and the hinging axis is rearward of the swivel axis.

CECIL W. BODE'N.

